Circuit-controlling device



Dec. 15 1925 1,566,122

F. ROBERSON CIRCUIT CONTROLLING DEYICE Filed May 16, 1925 T'nvehtor':Fromk Roberson, e! His Attorney Ill) Patented Dec. 15,

UNITED STATES PATENT OFFICE.

FRANK ROBERSON, OF GARY, INDIANA, ASSIGNOR T0 GENERAL ELECTRIC COMPANY,A CORPORATION OF NEW'YORKL CIRCUIT-CONTROLLING DEVICE.

Application filed May 16, 1925.

To all whom it may concern:

Be it known that I, FRANK RoBERsoN, a citizen of the United States,residing at Gary, in the county of Lake, State of Indiana, have inventedcertain new and useful Improvements in Circuit-Controlling Devices, ofwhich the following is a specification.

This invention relates to circuit controlling devices and moreparticularly to circuit interrupters of the high speed type which areelectro-magnetically held closed and arranged to quickly and positivelyopen to in terrupt an electric circuit in response to predeterminedconditions such as for instance an overload on the circuit.

The principal object of the present invention is to provide an improvedform of high speed circuit interrupter of the above character wherebythe speed at which the circuit is interrupted may be practicallydoubled.

A further object of the invention is to provide an improved form ofcircuit interrupter of the above type which is arranged to trip freeshould an excessive overload current flow upon the closure of theinterrupter.

Although not necessarily limited thereto, the present invention isparticularly well adapted to be applied to high speed electro magneticcircuit interr'upters of the type described and claimed in the reissuedPatent No. 15,441 issued August 29, 1922 to John F. Tritle. In theTritle type of circuit interrupter a movable switch arm is stronglybiased to the circuit interrupting position and is arranged to be heldin circuit closing engagement with the stationary switch contactcooperating therewith by the magnetic attraction of an electromagnet.Suitable means such as abucking bar energized responsively to thecurrent through the interrupter is provided for controlling the holding(-ilectromagnet to permit the switch memher to open quickly inaccordance with its bias upon the occurrence of overload conditions inthe controlled circuit. Quick acting circuit interrupters constructedand arranged in the manner described. in the above applicatlon areeminently successful in protecting electrical apparat-us such as dynamoelectric machines from heavy rushes of overload or short circuit currentwhich otherwise might cause the machines to flash over in a very shortinterl of ti e, However, when this type of Serial No. 30,738.

circuit interrupter is constructed in accordance with my presentinvention, the speed at which the overload or short circuit current isinterrupted is practically doubled. Thus by means of my presentinvention the Tritle type of interrupter is rendered-capable of stillmore effectively protecting against heavy rushes of current such asoocurunder severe short circuit conditions or the like.

In carrying the invention into efi'ect in a preferred form, I providethe circuit interrupter with a pair of cooperating independently movableswitch members which are each strongly biased to the circuitinterrupting position and are arranged to be operated into circuitclosing engagement. Also I provide an electromagnet preferably havingseparate poles for magnetically holding each of the switch members inthe circuit closing position. In order to simultaneously release themembers to permit them jointly to interrupt the circuit at twice theinterrupting speed of a single movable switch member, I associate aconductor or winding with the several poles of the holding electromagnetso as to simultaneously control the attractive force thereof to permitthe switch members to move quickly to their respective circuitinterrupting positions. The resultant separation of the cir cuitcontrolling switch members is effected at such a high rate of speed asto almost instantly interrupt even heavy short circuits.

Furthermore, since the cooperatingswitch members in the preferred formof my improved circuit interrupter are independently movable to and fromthe circuit closing posi tion the interrupter is capable of affordingoverload protection from the instant that the controlled circuit isclosed. This is due to the fact that theone of the switch members whichis initially operated to and held in the circuit closing position isfree to be released instantly should an overload current How in thecontrolled circuit when the second switch member is operated to thecircuit closing position.

For a. better understanding of my inven tion, reference is had to thefollowing de scription taken in connection with the accompanying drawingin whichFig. 1 diagrammatically illustrates a high speed electromagneticcircuit interrupter embodying the invention for the purpose ofexplaining the principles thereof, and Fig. 2 is a detailed view showingthe pole construction of the holding electromagnet with which theinterrupter shown in Fig. 1 is provided.

The novel features and combinations which I believe to be characteristicof my invention are pointed out with particularity in the appendedclaims. 7

Referring to Fig. 1, the circuit interrupter embodying my inventioncomprises essentially the two cooperating independently movable switchmembers 10 and 11 which are pivotally mounted to rotate respectivelyabout the pivots 14c and 15 and are each strongly biased to the circuitinterrupting position by means of the biasing springs 12 and 13respectively. It will be observed that the movable switch members areprovided with suitable yielding circuit controlling contacts 16 and 17respectively which are arranged to move into circuit closing engagementwhen the switch arms 10 and 11 are operated to their respective circuitclosing positions.

In order to hold the switch members 10 and ll in the circuit closingpositions in which they are shown, the magnetic members 18 and 19 aresuitably attached repectively to the switch members 10 and 11 and arearranged in magnetic attractive relation with the poles of the holdingelectromagnet 20. As shown, the holding electromagnet 20 is providedwith a holding winding 21 which. it will be understood normally isconnected to be energized from a suitable source of supply not shown inthe drawing. The mag-- netic structure of the holding electromagnet 20is divided and ofiset so as to provide a separate pair of poles forholding each of the magnetic members 18 and 19, as more clearly shown inFig. 2 Thus it will be seen that the operating flux of winding 21 whichpasses through the pair of poles serves'to magnetically attract themember 18 and thereby hold switch member 10 in the circuit closingposition when it is operated thereto through the agency of suitableclosin'g mechanism such as the combined manual. and electron'iagneti'cclosing device 23 illustrated in the drawing. In a similar manner, themagnetic member 19 is held under the magnetic influence of the pair ofpoles 2a to maintain the movable switch member 11 in the circuit closingposition when. operated thereto by' the closing device It will beobserved that the conductor 26, as shown, is connected in the circuitcontrolled by the interrupter which extends from the terminal 27 througha flexible connector to the contact 17, thence through the contact 16and a flexible coiinector connecting the latter to conductor 26 which isconnect'ed to the other terminal 28 of the interrupter. An intermediateportion of conductor 26 :is 'o'fl'set and l'ooji'd, as more may shown inFig. 2, to form a buckling bar for each of the pairs of poles 22 and 2tor the holding electromagnet 20 in order to effect the simultaneousrelease of the switch members 10 and 11 upon the occurrence of anoverload current in the circuit controlled by the interrupter. It willbe evident, however, that other suitable means energized responsively tothe current of the interrupter may be employed for controlling theholding electromagnet 20 to effect the simultaneous release of theswitch members 10 and 11 if desired.

With the circuit interrupter shown in Fig. 1 connected in a powercircuit to afford overload protection, the operation is as followsr-VVhen the current in the power circuit controlled by the interrupteris of normal value switch members 10 and 11 are held in their respectivepositions, as shown, with the circuit controlling contacts 16 and 17 incircuit closing engagement. How-- ever, upon the current in thecontrolled circuit increasing to an abnormal value due to overload,short circuit, or other abnormal conditions, the current passing throughconductor 26 is increased correspondingly. In a manner fully explainedin the Tritle reissue patent previously mentioned, the increased flow ofcurrent through the offset looped portion of conductor 26 forming thebucking bars for the poles 22 and 24: of holding electromagnet 20 servesto shift or transfer the flux of holding winding 21 passing through themagnetic members 18 and 19 away from the magnetic members through theair gap between the inner portions of the respective pair of poles. Inthis way, the attractive efiect of holding electromagnet 20 upon each ofthe magnetic members 18 and 19 is reduced sufficiently to permit thebiasing springs 12 and 13 to quickly operate the switch members 10 and11 substantially simultaneously to their respective circuit.interrupting positions. The combined movements-of switch members 10 and11 effects the separation of the circuit controlling contacts 16 and 17at an extremely high rate 01 speed. This permits the interrupter tosafely and successfully break the circuit almost instantly even thoughan extremely heavy overload. or short circuit current is flowingtherein.

The reclosure of the interrupter prefer ably is effected by operatingthe switch members 10 and 11 successively to their respective circuitclosing positions by means oi the closing devices 23 and respectively.Thus, when the circuit controlling member 10 is ii' itially operated tothe closed pO'Sltlflil and held therein by the magnetic attractionbetween the poles 22 of holding electromagnet 20 "and the magneticmember 18, member 1O willbe free .to be in antly operated to the':circuit interrupting p'esi lon y the biasing spring 12 should anoverload current flow through the conductor 26 when the switch member 11is operated to carry the circuit controlling contact 17 into circuitclosing engagement with the contact 16.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention together with theapparatus which I now consider to represent the best embodiment thereofbut I would have it understood thatthe apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is l. A high speed circuit interrupter com prising a pair ofcooperating independently movable circuit controlling contacts eachbiased to a position to interrupt the circuit jointly controlledthereby, an electromagnet having a magnetic movable member forcontrolling each of said contacts, the said electromagnet having aseparate flux path for magnetically holding each of said members in thecircuit closing position, and means responsive to the current in thecircuit controlled by the interrupter for simultaneously controlling theflux in said paths to release the said members.

2. A. high speed circuit interrupter comn'ising a pair of cooperatingindependently movable switch members operable into circuit closingengagement and each biased to the circuit interrupting position, anelectromagnet having a separate pair of poles for magnetically holdingeach of said members in the engaging position, and means energizedresponsively to the current in the circuit controlled by the interrupterand arranged to control the flux through said poles to release saidmembers substantially sinmltaneously.

3. A high speed circuit interrupter comprising a pair of pivotallymounted cooperating switch members each biased to the circuitinterrupting position and each having a movable magnetic member attachedthereto, a normally energized electromagnet having poles for separatelyholding each of said magnetic members when the corresponding switchmember is operated to the circuit closing position, and means responsireto the current in the circuit controlled by the interrupter forcontrolling the magnetic attraction between said poles and said membersto release the members substantially simultaneously under predeterminedcurrent conditions.

t A. high speed circuit interrupter con1- 1 ing a pair of pivotallymounted cooperfiring switch members operable into circuit closingengagement and each biased to the circuit interrupting position, a pairof movable magnetic members, each mechanically connected to acorresponding one of the said switch members, a normally energizedelectromagnet having separate poles for magnetically holding each ofsaid magnetic members when the corresponding switch member is operatedto the circuit closing position to hold the same therein, and aconductor connected to be energized responsively to the current in thecircuit controlled by the interrupter and associated with said poles tocontrol the flux thereof to release said magnetic members to permit saidswitch members to move out of engagement when the current in thecontrolled circuit exceeds a predetermined value.

5. A trip free circuit interrupter comprising a pair of cooperatingindependently movable circuit controlling members each biased to thecircuit interrupting position, means for separately operating each ofsaid members to the circuit closing position,

means for separately holding each of said members in the circuit closingposition com prising an electromagnet, and means responsive to thecurrent in the circuit controlled by the interrupter for controlling thesaid electromagnet to release one of said members when the currentexceeds a predetermined value upon the operation of the other member tothe circuit closing position.

6. A trip free circuit interrupter comprising a pair of cooperatingindependently movable switch members operable into circuit'closingengagement and each biased to the circuit interrupting position, anelectromagnet for separately holding each of said members in theengaging position, and means responsive to the current in the circuitcontrolled by the interrupter for controlling the said electromagnet torelease one of-said members when the current exceeds a predeterminedvalue upon the op eration of the other member to the circuit closingposition.

7. A high speed trip tlt'ree circuit interrupter comprising a pair ofpivotally mounted cooperating switch members each biased to the circuitinterrupting position and each having a movable magnetic mem berattached thereto, a normally energized GlGCtl'Oll'lfigIlOt havingseparate poles for holding each. of said magnetic members when thecorresponding switch member is operated to the circuit closing position,and a conductor connected to be energized responsively to the currentin. the circuit controlled by the interrupter for controlling the fluxthrough said poles to release one of said members when the currentexceeds a predetermined value upon the operation of the other member tothe circuit closing position.

In witness whereof I have hereunto set my hand this 7th day of Ma y,1925.

FRANK ROBERSON.

